/*

   Copyright 2002-2003  The Apache Software Foundation 

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

 */
package org.apache.batik.css.engine.value.svg;

import org.apache.batik.css.engine.CSSEngine;
import org.apache.batik.css.engine.CSSStylableElement;
import org.apache.batik.css.engine.StyleMap;
import org.apache.batik.css.engine.value.LengthManager;
import org.apache.batik.css.engine.value.ListValue;
import org.apache.batik.css.engine.value.Value;
import org.apache.batik.css.engine.value.ValueManager;
import org.apache.batik.util.CSSConstants;
import org.apache.batik.util.SVGTypes;

import org.w3c.css.sac.LexicalUnit;
import org.w3c.dom.DOMException;
import org.w3c.dom.css.CSSPrimitiveValue;
import org.w3c.dom.css.CSSValue;

/**
 * This class provides a manager for the 'enable-background' property values.
 *
 * @author <a href="mailto:stephane@hillion.org">Stephane Hillion</a>
 * @version $Id$
 */
public class EnableBackgroundManager extends LengthManager {
    
    /**
     * The length orientation.
     */
    protected int orientation;

    /**
     * Implements {@link ValueManager#isInheritedProperty()}.
     */
    public boolean isInheritedProperty() {
	return false;
    }

    /**
     * Implements {@link ValueManager#isAnimatableProperty()}.
     */
    public boolean isAnimatableProperty() {
        return false;
    }

    /**
     * Implements {@link ValueManager#isAdditiveProperty()}.
     */
    public boolean isAdditiveProperty() {
        return false;
    }

    /**
     * Implements {@link ValueManager#getPropertyType()}.
     */
    public int getPropertyType() {
        return SVGTypes.TYPE_ENABLE_BACKGROUND_VALUE;
    }

    /**
     * Implements {@link ValueManager#getPropertyName()}.
     */
    public String getPropertyName() {
	return CSSConstants.CSS_ENABLE_BACKGROUND_PROPERTY;
    }
    
    /**
     * Implements {@link ValueManager#getDefaultValue()}.
     */
    public Value getDefaultValue() {
        return SVGValueConstants.ACCUMULATE_VALUE;
    }

    /**
     * Implements {@link ValueManager#createValue(LexicalUnit,CSSEngine)}.
     */
    public Value createValue(LexicalUnit lu, CSSEngine engine)
        throws DOMException {
        switch (lu.getLexicalUnitType()) {
        case LexicalUnit.SAC_INHERIT:
            return SVGValueConstants.INHERIT_VALUE;

        default:
            throw createInvalidLexicalUnitDOMException
                (lu.getLexicalUnitType());

        case LexicalUnit.SAC_IDENT:
            String id = lu.getStringValue().toLowerCase().intern();
            if (id == CSSConstants.CSS_ACCUMULATE_VALUE) {
                return SVGValueConstants.ACCUMULATE_VALUE;
            }
            if (id != CSSConstants.CSS_NEW_VALUE) {
                throw createInvalidIdentifierDOMException(id);
            }
            ListValue result = new ListValue(' ');
            result.append(SVGValueConstants.NEW_VALUE);
            lu = lu.getNextLexicalUnit();
            if (lu == null) {
                return result;
            }
            result.append(super.createValue(lu, engine));
            for (int i = 1; i < 4; i++) {
                lu = lu.getNextLexicalUnit();
                if (lu == null){
                    throw createMalformedLexicalUnitDOMException();
                }
                result.append(super.createValue(lu, engine));
            }
            return result;
        }
    }

    /**
     * Implements {@link
     * ValueManager#createStringValue(short,String,CSSEngine)}.
     */
    public Value createStringValue(short type, String value,
                                   CSSEngine engine) {
	if (type != CSSPrimitiveValue.CSS_IDENT) {
            throw createInvalidStringTypeDOMException(type);
	}
	if (!value.equalsIgnoreCase(CSSConstants.CSS_ACCUMULATE_VALUE)) {
            throw createInvalidIdentifierDOMException(value);
        }
	return SVGValueConstants.ACCUMULATE_VALUE;
    }

    /**
     * Implements {@link ValueManager#createFloatValue(short,float)}.
     */
    public Value createFloatValue(short unitType, float floatValue)
	throws DOMException {
        throw createDOMException();
    }

    /**
     * Implements {@link
     * ValueManager#computeValue(CSSStylableElement,String,CSSEngine,int,StyleMap,Value)}.
     */
    public Value computeValue(CSSStylableElement elt,
                              String pseudo,
                              CSSEngine engine,
                              int idx,
                              StyleMap sm,
                              Value value) {
        if (value.getCssValueType() == CSSValue.CSS_VALUE_LIST) {
            ListValue lv = (ListValue)value;
            if (lv.getLength() == 5) {
                Value lv1 = lv.item(1);
                orientation = HORIZONTAL_ORIENTATION;
                Value v1 = super.computeValue(elt, pseudo, engine,
                                              idx, sm, lv1);
                Value lv2 = lv.item(2);
                orientation = VERTICAL_ORIENTATION;
                Value v2 = super.computeValue(elt, pseudo, engine,
                                              idx, sm, lv2);
                Value lv3 = lv.item(3);
                orientation = HORIZONTAL_ORIENTATION;
                Value v3 = super.computeValue(elt, pseudo, engine,
                                              idx, sm, lv3);
                Value lv4 = lv.item(4);
                orientation = VERTICAL_ORIENTATION;
                Value v4 = super.computeValue(elt, pseudo, engine,
                                              idx, sm, lv4);

                if (lv1 != v1 || lv2 != v2 ||
                    lv3 != v3 || lv4 != v4) {
                    ListValue result = new ListValue(' ');
                    result.append(lv.item(0));
                    result.append(v1);
                    result.append(v2);
                    result.append(v3);
                    result.append(v4);
                    return result;
                }
            }
        }
        return value;
    }

    /**
     * Indicates the orientation of the property associated with
     * this manager.
     */
    protected int getOrientation() {
        return orientation;
    }

}
